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I'm setting up a Debian Xen server for the first time, and so far it's gone smoothly. However, whenever I tried to enable VNC connections for a domain (by adding a vfb=... line to the config file), attempting to run xm create on the config file causes a crash with the following cryptic Python error:

Error: 'NoneType' object has no attribute 'rfind'

Some Google searching revealed that it's a bug in option parsing in whatever Python script starts the domains, but that tells me nothing about how to fix it. If I comment out the "vfb" line in the config file, the domain will start without any issues. My full config file for the domain is below:

# Configuration file for the Xen instance, created
# by xen-tools 4.2 on Thu Apr 26 15:40:33 2012.

#  Kernel + memory size

bootloader = '/usr/lib/xen-default/bin/pygrub'

vcpus       = '1'
memory      = '512'

#  Disk device(s).
root        = '/dev/xvda2 ro'
disk        = [

#  Physical volumes

#  Hostname
name        = ''

#  Networking
vif         = [ 'ip=,mac=00:16:3E:96:1A:FF,bridge=br0' ]

# Remote VNC Access
vfb = [ 'type=vnc' ]

#  Behaviour
on_poweroff = 'destroy'
on_reboot   = 'restart'
on_crash    = 'restart'

Any idea how to make this error stop? Is there something obvious I'm forgetting here?

(OS: Debian Squeeze, 32-bit)

share|improve this question
up vote 2 down vote accepted

I think this is what you're looking for:

apt-get install xen-qemu-dm-4.0

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This fixed my original problem, but now I am unable to access the VNC server after starting the domU, even though the domain starts without errors. This may be the best I can get though; I switched to just running a VNC server on the domU itself. Much less hassle. – Adam R. Nelson May 2 '12 at 0:11
Your problem seems to be solved, but you might want to add following to your domU configuration: vfb=[ "type=vnc,vncunused=0,vncdisplay=1,vnclisten=,keymap=ja" ] – Taisuke Yamada May 8 '12 at 5:29

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